生成pdf文件并打包zip下载

第一种写法，使用org.apache.tools.zip，具体流程：
1、逐个生成pdf文件
2、打包zip
3、下载
第二种写法，使用java.util.zip，这种写法没成功。
1、使用pdf文件流进行打包
2、下载
这里介绍第一种。

一、导入相应的依赖包

    com.itextpdf
    itextpdf
    5.5.13.2


    com.itextpdf
    itext-asian
    5.2.0



    org.apache.ant
    ant
    1.10.12

二、生成pdf 和 zip 文件

PdfUtil.java 关键代码

/**
* 创建document对象
*/
public static Document createDocument() {
   //生成pdf
   Document document = new Document();
   // 页面大小
   Rectangle rectangle = new Rectangle(PageSize.A4);
   // 页面背景颜色
   rectangle.setBackgroundColor(BaseColor.WHITE);
   document.setPageSize(rectangle);
   // 页边距 左，右，上，下
   document.setMargins(20, 20, 20, 20);
   return document;
}

/**
 * @param text 段落内容
 * @return
 */
public static Paragraph createParagraph(String text, Font font) {
   Paragraph elements = new Paragraph(text, font);
   elements.setSpacingBefore(5);
   elements.setSpacingAfter(5);
   elements.setSpacingAfter(spacing);
   return elements;
}

/**
 * 创建默认列宽，指定列数、水平(居中、右、左)的表格
 *
 * @param colNumber
 * @param align
 * @return
 */
public static PdfPTable createTable(int colNumber, int align) {
   PdfPTable table = new PdfPTable(colNumber);
   try {
      table.setTotalWidth(maxWidth);
      table.setLockedWidth(true);
      table.setHorizontalAlignment(align);
      table.getDefaultCell().setBorder(1);
   } catch (Exception e) {
      e.printStackTrace();
   }
   return table;
}

/**
* 创建单元格（指定字体、水平居..、单元格跨x列合并）
*
* @param value
* @param font
* @param align
* @param colspan
* @return
*/
public static PdfPCell createCell(String value, Font font, int align, int colspan) {
   PdfPCell cell = new PdfPCell();
   cell.setVerticalAlignment(Element.ALIGN_MIDDLE);
   cell.setHorizontalAlignment(align);
   cell.setColspan(colspan);
   cell.setPhrase(new Phrase(value, font));
   cell.setMinimumHeight(20f);
   return cell;
}

业务代码

/**
* 生成单个pdf文件，并返回文件对象
* @param dto 需要生成pdf的数据对象
* @return UploadResult 自定义文件对象
*/
private UploadResult generatePDF(ActivityApplyLogDto dto) {
     Document document = null;
     try {
         document = PdfUtil.createDocument();
         
		// 这里是返回一个pdf的存放地址和文件名，可自定义，如下
		// UploadResult rs = new UploadResult();
     	// rs.setPath(filePath);
		// rs.setName(fileName);			
      	 UploadResult fileUploadResult = fileService.getFilePath("pdf");
         FileOutputStream fos = new FileOutputStream(fileUploadResult.getPath());
         PdfWriter.getInstance(document, fos);
         document.open();

		 // 字体定义
         BaseFont bfChinese = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);
         Font titlefont = new Font(bfChinese, 16, Font.BOLD);
         Font textfont = new Font(bfChinese, 10, Font.NORMAL);

         // 生成居中标题
         Paragraph title = PdfUtil.createParagraph("活动报名信息\n", titlefont);
         title.setAlignment(Element.ALIGN_CENTER);
         document.add(title);
         document.add(new Paragraph("   "));

         PdfPTable table = PdfUtil.createTable(6, Element.ALIGN_CENTER);

         BizUser user = dto.getUser();
         BizActivity activity = dto.getActivity();
         table.addCell(PdfUtil.createCell("关联活动名称", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(activity.getName(), textfont, Element.ALIGN_LEFT, 2));
         table.addCell(PdfUtil.createCell("姓名", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(user.getName(), textfont, Element.ALIGN_LEFT, 2));

         table.addCell(PdfUtil.createCell("手机号码", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(user.getPhone(), textfont, Element.ALIGN_LEFT, 2));            
         table.addCell(PdfUtil.createCell("性别", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(user.getGender(), textfont, Element.ALIGN_LEFT, 2));

         table.addCell(PdfUtil.createCell("证件类型", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(user.getCardType(), textfont, Element.ALIGN_LEFT, 2));
         table.addCell(PdfUtil.createCell("证件号码", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(user.getCardNum(), textfont, Element.ALIGN_LEFT, 2));

         table.addCell(PdfUtil.createCell("报名状态", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(dto.getStatus(), textfont, Element.ALIGN_LEFT, 2));
         table.addCell(PdfUtil.createCell("报名时间", textfont, Element.ALIGN_LEFT, 1));
         table.addCell(PdfUtil.createCell(dto.getApplyTime(), textfont, Element.ALIGN_LEFT, 2));

         document.add(table);

         return fileUploadResult;
    }catch (Exception e) {
         throw new BadRequestException("生成失败");
    } finally {
         if (document != null) document.close();
    }
}

生成 zip 文件
ZipUtil.java 关键代码，参考了https://www.cnblogs.com/alphajuns/p/12442315.html的写法

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipFile;
import org.apache.tools.zip.ZipOutputStream;

public class ZipUtil {
    public static final String SYS_TEM_DIR = System.getProperty("java.io.tmpdir") + File.separator;
    
    /**
     * 这里先不关闭流，否则会报异常
     * @param zip      压缩目的地址
     * @param srcFiles 压缩的源文件     
     */
    public static String zipFile(String zip, List<File> srcFiles) throws Exception{
        String path = SYS_TEM_DIR + zip;
        FileOutputStream fos = new FileOutputStream(path);
        ZipOutputStream out = new ZipOutputStream(fos);
        out.setEncoding("GBK");
        for (File _f : srcFiles) {
            handlerFile(out, _f);
        }
        return path;
    }

    /**
     * 处理压缩
     * @param out 目标文件流
     * @param srcFile 源文件信息
     */
    private static void handlerFile(ZipOutputStream out, File srcFile) throws IOException {
        InputStream in = new FileInputStream(srcFile);
        out.putNextEntry(new ZipEntry(srcFile.getName()));
        int len = 0;
        byte[] _byte = new byte[1024];
        while ((len = in.read(_byte)) > 0) {
            out.write(_byte, 0, len);
        }
        in.close();
        out.closeEntry();
    }
}

三、下载

后台代码

public void downloadPDF(List<BizActivityApplyLogDto> all, HttpServletResponse response) throws Exception {
   List<File> fileList = new ArrayList<>();
   for (BizActivityApplyLogDto dto : all) {
       UploadResult rs = generatePDF(dto);
       fileList.add(new File(rs.getPath()));
   }
   //zip压缩包名称
   String zipFileName = "活动报名信息.zip";
   response.setCharacterEncoding("UTF-8");
   response.setContentType("application/octet-stream");
   String path = ZipUtil.zipFile(zipFileName, fileList);

   FileInputStream fileInputStream = new FileInputStream(path);
   //设置Http响应头告诉浏览器下载文件名 Filename
   response.setHeader("Content-Disposition", "attachment;Filename=" + URLEncoder.encode(zipFileName, "UTF-8"));
   OutputStream outputStream = response.getOutputStream();
   byte[] bytes = new byte[2048];
   int len = 0;
   while ((len = fileInputStream.read(bytes)) > 0) {
       outputStream.write(bytes, 0, len);
   }
   outputStream.flush();
   fileInputStream.close();
   outputStream.close();
}

前端代码

//点击导出按钮
<el-button type="primary" icon="el-icon-download" size="mini" :loading="exportLoading" @click="downloadPDF">导出PDF</el-button>

downloadPDF(){
  let total = this.page.total
  if (total == null || total == undefined || parseInt(total) <= 0) {
    this.$alert('没有数据可导出')
  }
  this.$confirm('确定导出结果列表中的'+ total +'个pdf文件吗？', '提示', {
    confirmButtonText: '确定',
    cancelButtonText: '取消',
    type: 'warning'
  }).then(() => {
    this.exportLoading = true
    download(this.baseUrl + '/downloadPDF', this.getParams()).then(res => {
      downloadFile(res, this.title + '数据', 'zip')
      this.exportLoading = false
    }).catch(()=>{
      this.exportLoading = true
    })
  })
}

// download 使用了axios 和 qs,
export function download(url, params) {
  return request({
    url: url + '?' + qs.stringify(params, { indices: false }),
    method: 'get',
    responseType: 'blob'
  })
}

// 下载文件
export function downloadFile(obj, name, suffix) {
  const url = window.URL.createObjectURL(new Blob([obj]))
  const link = document.createElement('a')
  link.style.display = 'none'
  link.href = url
  const fileName = parseTime(new Date()) + '-' + name + '.' + suffix
  link.setAttribute('download', fileName)
  document.body.appendChild(link)
  link.click()
  document.body.removeChild(link)
}